Interchangeable lens, camera body, and electronic device

ABSTRACT

An interchangeable lens to be detachably attached to a camera body, that includes a holding unit at which a plurality of contacts is arranged, the interchangeable lens includes: a first communication contact system arranged at the holding unit; and a second communication contact system different from the first communication contact system, arranged at the holding unit at a position different from a position at which the first communication contact system is arranged. The fourth contact is arranged at a position closer to the second communication contact system than the first contact, the second contact, and the third contact are, and the seventh contact and the eighth contact are arranged at positions closer to the first communication contact system than the fifth contact and the sixth contact are.

This is a Continuation of U.S. application Ser. No. 14/627,532 filed onFeb. 20, 2015 (now U.S. Pat. No. 9,823,548), which is a Continuation ofU.S. application Ser. No. 13/940,768 filed on Jul. 12, 2013 (now U.S.Pat. No. 8,995,069), which is a Continuation of U.S. application Ser.No. 13/745,464 filed Jan. 18, 2013 (now abandoned), which is aContinuation of U.S. application Ser. No. 13/033,166 filed Feb. 23, 2011(now U.S. Pat. No. 8,400,722), which claims the benefit of U.S.Provisional Application No. 61/425,506 filed Dec. 21, 2010, and U.S.Provisional Application No. 61/430,211 filed Jan. 6, 2011. Thisapplication also claims priority to Japanese Application No. 2010-202104filed Sep. 9, 2010, and Japanese Patent Application No. 2010-294513filed Dec. 29, 2010. The disclosure of each of the earlier applicationsis incorporated herein by reference in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an interchangeable lens, a camera bodyand an electronic device.

2. Description of Related Art

There has been known a camera which electrically performs communicationbetween the camera body and the interchangeable lens. Japanese PatentLaid-open Publication No. H07-234432 discloses an interchangeable lensthat includes terminals for communicating with the camera body andterminals for communicating with an adapter such as an intermediate ringor rear focus converter. These two types of terminals constitutecommunication systems. When an adapter is attached, the interchangeablelens first communicates with the adapter via one of the communicationsystems. Then, the interchangeable lens communicates with the camerabody via the other of the communication systems.

SUMMARY OF THE INVENTION

In the case of the camera body and interchangeable lens disclosed in theabove publication, there is the possibility that when communication isperformed by two independent communication systems simultaneously, thecommunication performed by one communication system could give anadverse effect on the communication performed by the other communicationsystem.

An interchangeable lens to be detachably attached to a camera body,according to 1st aspect of the present invention, that includes aholding unit at which a plurality of contacts is arranged, theinterchangeable lens comprises: a first communication contact systemarranged at the holding unit, including a first contact through which afirst clock signal output from the camera body is input, a secondcontact through which a first data signal output from the camera body insynchronization with the first clock signal is input, a third contactthrough which a second data signal is output to the camera body insynchronization with the first clock signal, and a fourth contactthrough which a first asynchronous signal that is asynchronous with thefirst clock signal is output to the camera body; and a secondcommunication contact system different from the first communicationcontact system, arranged at the holding unit at a position differentfrom a position at which the first communication contact system isarranged, the second communication contact system including a fifthcontact through which a second clock signal is output to the camerabody, a sixth contact through which a third data signal is output to thecamera body in synchronization with the second clock signal, a seventhcontact through which a second asynchronous signal that is asynchronouswith the second clock signal is input from the camera body, and aneighth contact through which a third asynchronous signal that isasynchronous with the second clock signal is output to the camera body,wherein: the fourth contact is arranged at a position closer to thesecond communication contact system than the first contact, the secondcontact, and the third contact are, and the seventh contact and theeighth contact are arranged at positions closer to the firstcommunication contact system than the fifth contact and the sixthcontact are.

An interchangeable lens to be detachably attached to a camera body,according to a 2nd aspect of the present invention, that includes aholding unit at which a plurality of contacts is arranged, theinterchangeable lens comprises: a first communication contact systemarranged at the holding unit, including a first contact through which afirst clock signal output from the camera body is input, a secondcontact through which a first data signal output from the camera body insynchronization with the first clock signal is input, a third contactthrough which a second data signal is output to the camera body insynchronization with the first clock signal, and a fourth contactthrough which a first asynchronous signal that is asynchronous with thefirst clock signal is output to the camera body; a second communicationcontact system different from the first communication contact system,arranged at the holding unit at a position different from a position atwhich the first communication contact system is arranged, the secondcommunication contact system including a fifth contact through which asecond clock signal is output to the camera body, a sixth contactthrough which a third data signal is output to the camera body insynchronization with the second clock signal, a seventh contact throughwhich a second asynchronous signal that is asynchronous with the secondclock signal is input from the camera body, and an eighth contactthrough which a third asynchronous signal that is asynchronous with thesecond clock signal is output to the camera body; a first communicationdevice that receives the first data signal from the camera body usingthe second contact and transmits the second data signal to the camerabody using the third contact based on the first asynchronous signaloutput from the fourth contact and the first clock signal input at thefirst contact; and a second communication device that transmits thethird data signal to the camera body using the sixth contact based onthe second asynchronous signal input at the seventh contact, the thirdasynchronous signal output from the eighth contact, and the second clocksignal input at the fifth contact, wherein: the fourth contact isarranged at a position closer to the second communication contact systemthan the first contact, the second contact, and the third contact are,and the seventh contact and the eighth contact are arranged at positionscloser to the first communication contact system than the fifth contactand the sixth contact are.

According to a 3rd aspect of the present invention the interchangeablelens according to the 1st aspect may further comprise: a driving devicethat drives a driven member; and a first power source contact systemarranged at the holding unit at a position different from positions atwhich the first communication contact system and the secondcommunication contact system are arranged, respectively, the first powersource contact system including a ninth contact through which a drivevoltage for driving the driving device is supplied from the camera body,and a tenth contact that is a ground germinal corresponding to the drivevoltage, wherein the first power source contact system is arrangedopposite to the first communication contact system with respect to thesecond communication contact system.

According to a 4th aspect of the present invention, in theinterchangeable lens according to the 3rd aspect, in the first powersource contact system, the tenth contact may be arranged closest to thesecond communication contact system.

According to a 5th aspect of the present invention, in theinterchangeable lens according to the 4th aspect, in the secondcommunication contact system, the sixth contact may be arranged closestto the tenth contact.

According to a 6th aspect of the present invention, the interchangeablelens according to the 5th aspect may further comprise: a second powersource contact system arranged at the holding unit at a positiondifferent from positions at which the first communication contactsystem, the second communication contact system, and the first powersource contact system are arranged, respectively, the second powersource contact system including an eleventh contact through which anoperation voltage having a different voltage value from the drivevoltage is supplied from the camera body, and a twelfth contact that isa ground terminal corresponding to the operation voltage, wherein: avalue of the operation voltage supplied to the eleventh contact issmaller than a value of the drive voltage supplied to the ninth contact;the first power source contact system is arranged opposite to the secondcommunication contact system with respect to the first communicationcontact system; and the twelfth contact is arranged at a position closerto the first communication contact system than the eleventh contact is.

According to a 7th aspect of the present invention, in theinterchangeable lens according to the 6th aspect, it is preferable that:the first contact is arranged opposite to the eleventh contact withrespect to the twelfth contact; the third contact is arranged oppositeto the second communication contact system with respect to the fourthcontact; the second contact is arranged between the first contact andthe third contact; the seventh contact is arranged opposite to the thirdcontact with respect to the fourth contact; and the eighth contact isarranged opposite to the fourth contact with respect to the seventhcontact.

According to a 8th aspect of the present invention, in theinterchangeable lens according to the 6th aspect, the eleventh contact,the twelfth contact, the first contact, the second contact, the thirdcontact, the fourth contact, the seventh contact, the eighth contact,the fifth contact, the sixth contact, the tenth contact, and the ninthcontact may be arranged in that order at the holding unit in the form ofa circular arc.

According to a 9th aspect of the present invention, in theinterchangeable lens according to the 6th aspect, a difference betweenan upper limit and a lower limit of current that flows through the tenthcontact may be greater than a difference between an upper limit and alower limit of current that flows through the twelfth contact.

According to a 10th aspect of the present invention, the interchangeablelens according to the 2nd aspect may further comprise: a driving devicethat drives an optical member; a first power source contact systemarranged at the holding unit at a position different from positions atwhich the first communication contact system and the secondcommunication contact system are arranged, respectively, the first powersource contact system including a ninth contact through which a drivevoltage for driving the driving device is supplied from the camera body,and a tenth contact that is a ground terminal corresponding to the drivevoltage; and a second power source contact system arranged at theholding unit at a position different from positions at which the firstcommunication contact system, the second communication contact system,and the first power source contact system are arranged, respectively,the second power source contact system including an eleventh contactthrough which an operation voltage for the first communication deviceand the second communication device are supplied from the camera body,and a twelfth contact that is a ground terminal corresponding to theoperation voltage, wherein: a value of the operation voltage supplied tothe eleventh contact is smaller than a value of the drive voltagesupplied to the ninth contact; the first power source contact system isarranged opposite to the second communication contact system withrespect to the first communication contact system; the twelfth contactis arranged at a position closer to the first communication contactsystem than the eleventh contact is; the first contact is arrangedopposite to the eleventh contact with respect to the twelfth contact;the third contact is arranged opposite to the second communicationcontact system with respect to the fourth contact; the second contact isarranged between the first contact and the third contact; the seventhcontact is arranged opposite to the third contact with respect to thefourth contact; and the eighth contact is arranged opposite to thefourth contact with respect to the seventh contact.

According to a 11th aspect of the present invention, in interchangeablelens according to the 2nd aspect, one of the first communication deviceand the second communication device may be capable of performingcommunication with the camera body even when another of the firstcommunication device and the second communication device performscommunication with the camera body.

An interchangeable lens to be detachably attached to a camera body,according to a 12th aspect of the present invention, that includes adriven member, the interchangeable lens comprises: a first contactthrough which a first clock signal output from the camera body is input;a second contact through which a first data signal output from thecamera body in synchronization with the first clock signal is input; athird contact through which a second data signal is output to the camerabody in synchronization with the first clock signal; a fourth contactthrough which a first asynchronous signal that is asynchronous with thefirst clock signal is output to the camera body; a fifth contact throughwhich a second clock signal is output to the camera body; a sixthcontact through which a third data signal is output to the camera bodyin synchronization with the second clock signal; a seventh contactthrough which a second asynchronous signal that is asynchronous with thesecond clock signal is input from the camera body; an eighth contactthrough which a third asynchronous signal that is asynchronous with thesecond clock signal is output to the camera body; a ninth contactthrough which a drive voltage for driving the driven member is suppliedfrom the camera body; a tenth contact that is a ground germinalcorresponding to the drive voltage; an eleventh contact through which anoperation voltage having a different voltage value from the drivevoltage is supplied from the camera body; a twelfth contact that is aground terminal corresponding to the operation voltage; and a holdingunit at which the first to twelfth contacts are arranged, wherein: theeleventh contact is arranged on one end and the ninth contact isarranged on another end of the arrangement of the twelve contacts; thetwelfth contact is arranged next to the eleventh contact in thearrangement of the twelve contacts; the first contact is arrangedopposite to the eleventh contact with respect to the twelfth contact inthe arrangement of the twelve contacts; the second contact is arrangedopposite to the twelfth contact with respect to the first contact in thearrangement of the twelve contacts; the third contact is arrangedopposite to the first contact with respect to the second contact in thearrangement of the twelve contacts; the fourth contact is arrangedopposite to the third contact with respect to the second contact in thearrangement of the twelve contacts; the seventh contact is arrangedopposite to the third contact with respect to the fourth contact in thearrangement of the twelve contacts; the eighth contact is arrangedopposite to the fourth contact with respect to the seventh contact inthe arrangement of the twelve contacts; the fifth contact is arrangedopposite to the seventh contact with respect to the eighth contact inthe arrangement of the twelve contacts; the sixth contact is arrangedopposite to the fifth contact with respect to the eighth contact in thearrangement of the twelve contacts; and the tenth contact is arrangedopposite to the fifth contact with respect to the sixth contact and nextto the ninth contact in the arrangement of the twelve contacts.

According to a 13th aspect of the present invention, in theinterchangeable lens according to the 12th aspect, a value of the drivevoltage may be greater than a value of the operation voltage.

According to a 14th aspect of the present invention, in theinterchangeable lens according to the 1st aspect, the driven member mayinclude any of a member movable in a direction of optical axis of anoptical system, a member movable in a direction perpendicular to theoptical axis, and a member that is movable so as to change a size of anaperture through which a light flux passes.

A camera body, according to a 15th aspect of the present invention,which an interchangeable lens is to be detachably attached to and whichincludes a holding unit at which a plurality of contacts is arranged,the camera body comprises: a first communication contact system arrangedat the holding unit, including a first contact through which a firstclock signal is output to the interchangeable lens, a second contactthrough which a first data signal is output to the interchangeable lensin synchronization with the first clock signal, a third contact throughwhich a second data signal is input from the interchangeable lens insynchronization with the first clock signal, and a fourth contactthrough which a first asynchronous signal that is asynchronous with thefirst clock signal is input from the interchangeable lens; and a secondcommunication contact system different from the first communicationcontact system, arranged at the holding unit at a position differentfrom a position at which the first communication contact system isarranged, the second communication contact system including a fifthcontact through which a second clock signal is output to theinterchangeable lens, a sixth contact through which a third data signalis input from the interchangeable lens in synchronization with thesecond clock signal, a seventh contact through which a secondasynchronous signal that is asynchronous with the second clock signal isoutput to the interchangeable lens, and an eighth contact through whicha third asynchronous signal that is asynchronous with the second clocksignal is input from the interchangeable lens, wherein: the fourthcontact is arranged at a position closer to the second communicationcontact system than the first contact, the second contact, and the thirdcontact are; and the seventh contact and the eighth contact are arrangedat positions closer to the first communication contact system than thefifth contact and the sixth contact are.

A camera body, according to a 16th aspect of the present invention,which an interchangeable lens is to be detachably attached to and whichincludes a holding unit at which a plurality of contacts is arranged,the camera body comprises: a first communication contact system arrangedat the holding unit, including a first contact through which a firstclock signal is output to the interchangeable lens, a second contactthrough which a first data signal is output to the interchangeable lensin synchronization with the first clock signal, a third contact throughwhich a second data signal is input from the interchangeable lens insynchronization with the first clock signal, and a fourth contactthrough which a first asynchronous signal that is asynchronous with thefirst clock signal is input from the interchangeable lens; a secondcommunication contact system different from the first communicationcontact system, arranged at the holding unit at a position differentfrom a position at which the first communication contact system isarranged, the second communication contact system including a fifthcontact through which a second clock signal is output to theinterchangeable lens, a sixth contact through which a third data signalis input from the interchangeable lens in synchronization with thesecond clock signal, a seventh contact through which a secondasynchronous signal that is asynchronous with the second clock signal isoutput to the interchangeable lens, and an eighth contact through whicha third asynchronous signal that is asynchronous with the second clocksignal is input from the interchangeable lens; a first communicationdevice that transmits the first data signal to the interchangeable lensusing the second contact and receives the second data signal from theinterchangeable lens using the third contact based on the firstasynchronous signal input at the fourth contact and the first clocksignal output from the first contact; and a second communication devicethat receives the third data signal from the interchangeable lens usingthe sixth contact based on the second asynchronous signal output fromthe seventh contact, the third asynchronous signal input at the eighthcontact, and the second clock signal output from the fifth contact,wherein: the fourth contact is arranged at a position closer to thesecond communication contact system than the first contact, the secondcontact, and the third contact are; and the seventh contact and theeighth contact are arranged at positions closer to the firstcommunication contact system than the fifth contact and the sixthcontact are.

According to a 17th aspect of the present invention, the camera bodyaccording to the 15th aspect may further comprise: a first power sourcecontact system arranged at the holding unit at a position different frompositions at which the first communication contact system and the secondcommunication contact system are arranged, respectively, the first powersource contact system including a ninth contact through which a drivevoltage for driving a driven member of the interchangeable lens issupplied, and a tenth contact that is a ground terminal corresponding tothe drive voltage, wherein: the first power source contact system isarranged opposite to the first communication contact system with respectto the second communication contact system.

According to a 18th aspect of the present invention, in the camera bodyaccording to the 17th aspect, in the first power source contact system,the tenth contact may be arranged closest to the second communicationcontact system.

According to a 19th aspect of the present invention, in the camera bodyaccording to the 18th aspect, in the second power source contact system,the sixth contact may be arranged closest to the tenth contact.

According to a 20th aspect of the present invention, the camera bodyaccording to the 19th aspect may further comprise: a second power sourcecontact system arranged at the holding unit at a position different frompositions at which the first communication contact system, the secondcommunication contact system, and the first power source contact systemare arranged, respectively, the second power source contact systemincluding an eleventh contact through which an operation voltage havinga different voltage value from the drive voltage is supplied to theinterchangeable lens, and a twelfth contact that is a ground terminalcorresponding to the operation voltage, wherein: a value of theoperation voltage supplied to the eleventh contact is smaller than avalue of the drive voltage supplied to the ninth contact; the firstpower source contact system is arranged opposite to the secondcommunication contact system with respect to the first communicationcontact system; and the twelfth contact is arranged at a position closerto the first communication contact system than the eleventh contact is.

According to a 21st aspect of the present invention, in the camera bodyaccording to the 20th aspect, it is preferable that: the first contactis arranged opposite to the eleventh contact with respect to the twelfthcontact; the third contact is arranged opposite to the secondcommunication contact system with respect to the fourth contact; thesecond contact is arranged between the first contact and the thirdcontact; the seventh contact is arranged opposite to the third contactwith respect to the fourth contact; and the eighth contact is arrangedopposite to fourth contact with respect to the seventh contact.

A camera body, according to a 22nd aspect of the present invention,which an interchangeable lens including a driven member is to bedetachably attached, the interchangeable lens comprises: a first contactthat outputs a first clock signal to the interchangeable lens; a secondcontact outputs a first data signal to the interchangeable lens insynchronization with the first clock signal; a third contact that inputsa second data signal from the interchangeable lens in synchronizationwith the first clock signal; a fourth contact that inputs a firstasynchronous signal that is asynchronous with the first clock signalfrom the interchangeable lens; a fifth contact that outputs a secondclock signal; a sixth contact that inputs a third data signal from theinterchangeable lens in synchronization with the second clock signal; aseventh contact that outputs a second asynchronous signal that isasynchronous with the second clock signal to the interchangeable lens;an eighth contact that inputs a third asynchronous signal that isasynchronous with the second clock signal from the interchangeable lens;a ninth contact that supplies a drive voltage for driving the drivenmember of the interchangeable lens; a tenth contact that is a groundterminal corresponding to the drive voltage; an eleventh contact thatsupplies an operation voltage having a value different from a value ofthe drive voltage to the interchangeable lens; a twelfth contact that isa ground terminal corresponding to the operation voltage; and a holdingunit at which the first to twelfth contacts are arranged, wherein: theeleventh contact is arranged on one end and the ninth contact isarranged on another end of the arrangement of the twelve contacts; thetwelfth contact is arranged next to the eleventh contact in thearrangement of the twelve contacts; the first contact is arrangedopposite to the eleventh contact with respect to the twelfth contact inthe arrangement of the twelve contacts; the second contact is arrangedopposite to the twelfth contact with respect to the first contact in thearrangement of the twelve contacts; the third contact is arrangedopposite to the first contact with respect to the second contact in thearrangement of the twelve contacts; the fourth contact is arrangedopposite to the third contact with respect to the second contact in thearrangement of the twelve contacts; the seventh contact is arrangedopposite to the third contact with respect to the fourth contact in thearrangement of the twelve contacts; the eighth contact is arrangedopposite to the fourth contact with respect to the seventh contact inthe arrangement of the twelve contacts; the fifth contact is arrangedopposite to the seventh contact with respect to the eighth contact inthe arrangement of the twelve contacts; the sixth contact is arrangedopposite to the fifth contact with respect to the eighth contact in thearrangement of the twelve contacts; and the tenth contact is arrangedopposite to the fifth contact with respect to the sixth contact and nextto the ninth contact in the arrangement of the twelve contacts.

An electronic device, according to a 23rd aspect of the presentinvention, which an interchangeable lens including a driven member is tobe detachably attached, the electronic device comprises: a first contactthat outputs a first clock signal to the interchangeable lens; a secondcontact outputs a first data signal to the interchangeable lens insynchronization with the first clock signal; a third contact that inputsa second data signal from the interchangeable lens in synchronizationwith the first clock signal; a fourth contact that inputs a firstasynchronous signal that is asynchronous with the first clock signalfrom the interchangeable lens; a fifth contact that outputs a secondclock signal; a sixth contact that inputs a third data signal from theinterchangeable lens in synchronization with the second clock signal; aseventh contact that outputs a second asynchronous signal that isasynchronous with the second clock signal to the interchangeable lens;an eighth contact that inputs a third asynchronous signal that isasynchronous with the second clock signal from the interchangeable lens;a ninth contact that supplies a drive voltage for driving the drivenmember of the interchangeable lens; a tenth contact that is a groundterminal corresponding to the drive voltage; an eleventh contact thatsupplies an operation voltage having a value different from a value ofthe drive voltage to the interchangeable lens; a twelfth contact that isa ground terminal corresponding to the operation voltage; and a holdingunit at which the first to twelfth contacts are arranged, wherein: theeleventh contact is arranged on one end and the ninth contact isarranged on another end of the arrangement of the twelve contacts; thetwelfth contact is arranged next to the eleventh contact in thearrangement of the twelve contacts; the first contact is arrangedopposite to the eleventh contact with respect to the twelfth contact inthe arrangement of the twelve contacts; the second contact is arrangedopposite to the twelfth contact with respect to the first contact in thearrangement of the twelve contacts; the third contact is arrangedopposite to the first contact with respect to the second contact in thearrangement of the twelve contacts; the fourth contact is arrangedopposite to the third contact with respect to the second contact in thearrangement of the twelve contacts; the seventh contact is arrangedopposite to the third contact with respect to the fourth contact in thearrangement of the twelve contacts; the eighth contact is arrangedopposite to the fourth contact with respect to the seventh contact inthe arrangement of the twelve contacts; the fifth contact is arrangedopposite to the seventh contact with respect to the eighth contact inthe arrangement of the twelve contacts; the sixth contact is arrangedopposite to the fifth contact with respect to the eighth contact in thearrangement of the twelve contacts; and the tenth contact is arrangedopposite to the fifth contact with respect to the sixth contact and nextto the ninth contact in the arrangement of the twelve contacts.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 presents a perspective view showing a camera system withinterchangeable lenses according to the present invention;

FIG. 2 presents a cross-sectional view showing a camera system withinterchangeable lenses according to the present invention;

FIG. 3 presents a schematic diagram showing details of holding units;

FIGS. 4A and 4B present front views showing lens mounts;

FIG. 5 presents a timing chart illustrating an example of command datacommunication; and

FIGS. 6A and 6B present timing charts illustrating examples of hot linecommunication.

DETAILED DESCRIPTION OF THE INVENTION

First Embodiment

FIG. 1 presents a perspective view showing a camera system withinterchangeable lenses according to the present invention. In FIG. 1,only equipment and devices that relate to the present invention areshown but illustration and explanation on other equipment and devicesare omitted. A camera 1 includes a camera body 100 and aninterchangeable lens 200 that is detachably attached to the camera body100.

The camera body 100 is provided with a lens mount 101 which theinterchangeable lens 200 can be detachably attached to. As shown in FIG.4B, a holding unit that holds contacts (electrical connection part) 102is provided at a position near the lens mount 101 (on an inner peripheryside) of the camera body 100 such that the holding unit 102 partiallyprojects on the inner periphery side of the lens mount 101. The holdingunit 102 is provided with a plurality of contacts.

The interchangeable lens 200 is provided with a lens mount 201corresponding to the lens mount 101 on the camera body side, to whichthe camera body 100 can be detachably attached. As shown in FIG. 4B, aholding unit 202 is provided at a position near the lens mount 201 (onan inner periphery side) of the interchangeable lens 200 such that theholding unit 202 partially projects on the inner periphery side of thelens mount 201. The holding unit is provided with a plurality ofcontacts.

When the interchangeable lens 200 is attached to the camera body 100,the holding unit 102 provided with a plurality of contacts (which willbe described later in detail) is electrically and physically connectedto the holding unit 202 provided with a plurality of contacts (whichwill be described later in detail). The holding units 102 and 202 areused for supplying power from the camera body 100 to the interchangeablelens 200 and for transmitting and receiving signals between the camerabody 100 and the interchangeable lens 200.

At the back of the lens mount 101 in the camera body 100, there isprovided an image sensor 104. Above the camera body 100, there isprovided a button 107 that serves as an input device. The user may sendinstructions to the camera body for imaging and for setting imagingconditions.

FIG. 2 presents a cross-sectional view showing a camera system withinterchangeable lenses according to the present invention. Theinterchangeable lens 200 includes an imaging optical system 210 thatforms an image of a subject. The imaging optical system 210 includes aplurality of lenses 210 a to 210 c. The plurality of lenses 210 a to 210c includes a focusing lens 210 b that controls a point of focus of asubject image.

Inside the interchangeable lens 200, there is provided a lens-sidecontrol unit 203 that controls each unit of the interchangeable lens200. The lens-side control unit 203 includes a microcomputer (not shown)and its peripheral circuits (not shown). The lens-side control unit 203is connected to a lens-side first communication unit 217, a lens-sidesecond communication unit 218, a lens driving unit 212, a lensposition-detecting unit 213, a ROM 215, and a RAM 216.

The lens-side first communication unit 217 and the lens-side secondcommunication unit 218 transmit and receive data to and from the camerabody 100 through the holding units 102, 202, respectively. The lens-sidefirst communication unit 217 and the lens-side second communication unit218 are lens-side communication interfaces, respectively. A lens CPU 203performs communications (hot-line communication and command datacommunication) which will be described later between it and the camerabody 100 (a body-side control unit 103 on the camera side, which will bedescribed later) by using these communication interfaces,

The lens driving unit 212 has an actuator such as a stepping motor anddrives the focusing lens 210 b in response to a signal that is input tothe lens driving unit 212. A lens position-detecting unit 213 counts thenumber of pulses that are input to the stepping motor in the lensdriving unit 212 and detects the position of the focusing lens 210 b.Alternatively, the position of the focusing lens 210 b may be detectedby using a well-known distance encoder or the like provided in theinterchangeable lens 200.

A driven member other than the focusing lens 210 b may be provided inthe interchangeable lens 200. For example, similarly to the focusinglens 210 b, there may be provided, in the interchangeable lens 200, azoom lens as a member that can move in the direction of an optical axisof the interchangeable lens (imaging optical system 210) and a mechanismthat electrically drives the zoom lens (which is also referred to as“power zoom mechanism”). Also, there may be provided, in theinterchangeable lens 200, an image blur correction mechanism includingan image blur correction lens that can move in a moving directioncontaining components (X- and Y-direction components) perpendicular tothe direction of the optical axis of the imaging optical system 210. Theimage blur correction mechanism drives the image blur correction lens toperform image blur correction. Furthermore, there may be provided, inthe interchangeable lens 200, a power diaphragm mechanism that controlsdriving of diaphragm members (diaphragm blades), which are movable sothat they can change the size of the aperture through which light fluxfrom a subject passes. When such a driven member is provided, thelens-side control unit 203 controls the image blur correction lens, thediaphragm members, and the zoom lens for their driving and positiondetection by using the lens driving unit 212 and the lens positiondetecting unit 213.

The ROM 215 is a nonvolatile storage medium, in which a predeterminedcontrol program or the like to be executed by the lens-side control unit203 is stored in advance.

The RAM 216 is a volatile storage medium, which is used as a storagearea in which various data are stored by the lens-side control unit 203.

In front of the image sensor 104, there is provided a shutter 115 thatcontrols an exposure state of the image sensor 104, and an opticalfilter 116 that is combined with an optical low pass filter or aninfrared cut filter in combination. A subject light that has beentransmitted through the imaging optical system 210 is input to the imagesensor 104 through the shutter 115 and the filter 116.

Inside the camera body 100, there is provided a body-side control unit103 that controls each unit of the camera body 100. The body-sidecontrol unit 103 includes a microcomputer (not shown), a RAM (not shown)and peripheral circuits therefor (not shown).

The body-side control unit 103 is connected to a body-side firstcommunication unit 117 and a body-side second communication unit 118.The body-side first communication unit 117 is connected to the holdingunit 102 and can transmit data to and receive data from the lens-sidefirst communication unit 217. Similarly, the body-side secondcommunication unit 118 can transmit data to and receive data from thelens-side second communication unit 218. In other words, the body-sidefirst communication unit 117 and the body-side communication unit 118are communication interfaces, respectively, on the body side. Thebody-side control 103 performs communications (hot-line communicationand command data communication) which will be described later between itand the interchangeable lens 200 (lens-side control unit 203) by usingthese communication interfaces.

On the back side of the camera body 100, there is arranged a displayunit 111 including an LCD panel or the like. The body-side control unit103 an image of a subject based on the output from the image sensor 104(so-called “through-image”) and various menu screens for setting variousconditions including conditions for imaging.

Explanation on Holding Units 102, 202

FIG. 3 presents a schematic diagram showing details of the holding units102, 202. FIG. 3 schematically illustrates the structure of the mount.As a result, the lens mount and the holding unit 102 of the camera body100 are shown to be present on the same plane. However, in the actualstructure of the mount, the holding unit 102 is set back far from amount surface of the lens mount 101 of the camera body 100 (positionedon the right hand side with respect to the lens mount 101 in FIG. 3).

Also, FIG. 3 schematically illustrates the structure of the mount on theinterchangeable lens side and the lens mount 201 of the interchangeablelens 200 and the holding unit 202 are shown to be present on the sameplane. However, in actuality, the holding unit 202 is arranged at aposition projected from the mount surface of the lens mount 101(positioned on the right hand side with respect to the lens mount 201 inFIG. 3). As such, when the mount surface of the lens mount 101 and themount surface of the lens mount 201 are brought in contact with eachother to mount and connect the camera body 100 and the interchangeablelens 200, the holding unit 102 and the holding unit 202 are connected toeach other and hence the electric contacts provided in the holding unitsalso come to be connected to each other. Such a mount structure per seis well known and further explanation and illustration thereof isomitted here.

As shown in FIG. 3, twelve contacts BP1 to BP12 are present in theholding unit 102. Also, in the holding unit 202, there are twelvecontacts LP1 to LP12 that correspond to BP1 to BP12, respectively.

The contacts BP1 and BP2 are connected to a first power circuit 120 inthe camera body 100. The first power circuit 120 supplies to the contactBP1 operation voltage for each unit in the interchangeable lens 200exclusive of the lens driving unit 212. That is, the contacts BP1 andLP1 supply operation voltage to each unit in the interchangeable lens200 exclusive of the lens driving unit 212 (including a lens-side firstcommunication unit 217 and a lens-side second communication unit 218). Avalue of voltage that can be supplied to the contact BP1 is within therange of a minimum voltage value and a maximum voltage value (forexample, in a voltage width in the order of 3 V). However, the value ofvoltage that is normally supplied is near an intermediate value of themaximum and minimum voltage values. From this it follows that thecurrent value of current that is supplied from the camera body 100 tothe interchangeable lens 200 is about several tens milliamperes (mA) toseveral hundreds milliamperes (mA) when the power is ON.

The contact BP2 is a ground terminal corresponding to the operationvoltage given to the contact BP1. That is, the contacts BP2 and LP2 areground terminals corresponding to the operation voltage.

In the following explanation, a signal line via the contact BP1 and thecontact LP1 is referred to as a signal line V33. A signal line via thecontacts BP2 and LP2 is referred to as a signal line GND. The contactsLP1, LP2, BP1, and BP2 constitute a power source system contactsdedicated for supplying power from the camera body 100 side to theinterchangeable lens 200 side.

The contacts BP3, BP4, BP5, and BP6 are connected to the body-side firstcommunication unit 117. The contacts LP3, LP4, LP5, and LP6 on theinterchangeable lens 200 side corresponding to the contacts BP3, BP4,BP5, and BP6, respectively, are connected to the lens-side firstcommunication unit 217. The body-side first communication unit 117 andthe lens-side first communication unit 217 transmit and receive datatherebetween using these contacts (communication system contacts). Thecontents of communication performed between the body-side firstcommunication unit 117 and the lens-side first communication unit 217will be described in detail later.

In the following explanation, a signal line via the contacts BP3 and LP3is referred to as a signal line CLK. Similarly, a signal line via thecontacts BP4 and LP4 is referred to as a signal line BDAT, a signal lingvia the contacts BP5 and LP5 is referred to as a signal line LDAT, and asignal line via the contacts BP6 and LP6 is referred to as a signal lineRDY.

The contacts BP7, BP8, BP9, and BP10 are connected to the body-sidesecond communication unit 118. The contacts LP7, LP8 LP9, and LP10 onthe interchangeable lens 200 side corresponding to the contacts BP′7,BP8, BP9, and BP10, respectively, are connected to the lens-side secondcommunication unit 218. The lens-side second communication unit 218transmits data to and receives data from the body-side secondcommunication unit 118 using these contacts (communication contacts).The contents of communication between the body-side second communicationunit 118 and the lens-side second communication unit 218 will bedescribed in detail later.

In the following explanation, a signal line via the contacts BP7 and LP7is referred to as a signal line HREQ. Similarly, a signal line via thecontacts BP8 and LP8 is referred to as a signal line HANS, a signal lingvia the contacts BP9 and LP9 is referred to as a signal line HCLK, and asignal line via the contacts BP10 and LP10 is referred to as a signalline HDAT.

The contacts BP11 and BP12 are connected to a second power circuit 121in the camera body 100. The second power circuit 121 also supplies tothe contact BP12 driving voltage for driving the lens driving unit 212.That is, driving voltage for driving the driving unit 212 is suppliedfrom the contacts BP12 and LP12. The second power circuit 121 suppliesground voltage corresponding to the operation voltage. That is, groundvoltage corresponding to the driving voltage is supplied from thecontacts BP11 and LP11. A value of voltage that can be supplied to thecontact BP12 is within the range of a minimum voltage value and amaximum voltage value. The range of the voltage value for the contactBP12 is greater than the range of voltage value that can be supplied tothe contact BP1 (for example, the maximum value of the voltage that canbe supplied to the contact BP12 is on the order of several times themaximum value of the voltage that can be supplied to the contact BP1).That is, the value of the voltage supplied to the contact BP12 differsin magnitude from the value of the voltage supplied to the contact BP1.The value of the voltage normally supplied to the contact BP12 is nearan intermediate value of the maximum and minimum voltage values. Fromthis it follows that the current value of current that is supplied fromthe camera body 100 to the interchangeable lens 200 is about severaltens milliamperes (mA) to several amperes (A) when the power is ON.

The contact BP11 is a ground terminal corresponding to the drive voltagegiven to the contact BP12. That is, the contacts BP11 and the contactLP11 are ground terminals corresponding to the drive voltage.

In the following explanation, a signal line via the contacts BP11 andLP11 is referred to as a signal line PGND. A signal line via thecontacts BP12 and LP12 is referred to as a signal line BAT. The contactsLP11, LP12, BP11, and BP12 constitute power source system contactsdedicated for supplying power from the camera body 100 side to theinterchangeable lens 200 side.

From the magnitude relation between the value of the voltage (value ofcurrent) supplied to the contact BP12 and the contact LP12 and the valueof the voltage (value of current) supplied to the contact BP1 and thecontact LP1, the following is apparent. That is, a difference between amaximum value and a minimum value of current that flows through thecontacts BP11 and LP11 that serve as ground terminals for voltagessupplied to the respective contacts is greater than a difference betweena maximum value and a minimum value of current that flows through thecontacts BP2 and LP2. This is due to the fact that the driving unit 212having a driving system such as an actuator consumes more power thanthat consumed by an electronic circuit of the lens-side control unit 203or the like in the interchangeable lens 200 and that when the focus lens210 b does not have to be driven, the lens driving unit 212 consumes nopower.

FIGS. 4A and 4B present front views showing the lens mounts 101 and 201,respectively. FIG. 4A prevents a diagram showing the lens mount 201 forthe interchangeable lens 200 as seen from the camera body 100 side. FIG.4B presents a diagram showing the lens mount 101 for the camera body 100as seen from the interchangeable lens 200 side.

As shown in FIG. 4A, the contacts LP3, LP4, LP5, and LP6 are arranged inan orderly fashion in the form of a circular arc in the direction alongthe lens mount 201 (circumferential direction along a part of the lensmount having a substantially circular shape) in the holding unit 202.The contacts LP7, LP8, LP9, and LP10 are arranged in an orderly fashionin the form of a circular arc in a direction of extension of thedirection in which the contacts LP3 to LP6 is arranged. Here, thecontact LP6 is arranged at a position closer to the contacts LP7 to LP10than to the contacts LP3 to LP5. The contacts LP7 and LP8 are arrangedat respective positions closer to the contacts LP3 to LP6 than thecontacts LP9 and LP10 are.

The contacts LP11 and LP12 are arranged in an orderly fashion in theform of a circular arc in a direction of extension of the direction inwhich the contacts LP3 to LP6 are arranged (circumferential direction).The contacts LP7 to LP10 are arranged between the contacts LP3 to LP6and the contacts LP11 and LP12. The contact LP 10 is arranged next tothe contact LP11.

The contacts LP1 and LP2 are arranged in an orderly fashion in the formof a circular arc in a direction of extension of the direction in whichthe contacts LP3 to LP6 are arranged (circumferential direction). Thecontacts LP3 to LP6 are arranged between the contacts LP7 to LP10 andthe contacts LP1 and LP2. The contact LP2 is arranged at a positioncloser to the contacts LP3 to LP6 than the contact LP is.

That is, the twelve contacts LP1 to LP12 are arranged in an orderlyfashion in the form of a circular arc. In the present embodiment, anangle of θ 1 of the circular arc (a sector formed by connecting thecenter of the mount, the center of the contact LP1 and the center of thecontact LP12) is about 105 degrees. An angle of arc θ2 between any twoadjacent contacts is about 9.5 degrees. In the present embodiment, thewidth in the circumferential direction of each of the twelve contacts isabout 1.5 mm. The distance between the center of mount and the center ofeach contact (LP1 to LP12) is about 15 mm. Therefore, the distancebetween the centers of any adjacent two contacts in the circumferentialdirection is about 2.5 mm. Since the width of each contact in thecircumferential direction is about 1 mm, the clearance between any twoadjacent contacts in the circumferential direction is about 1 mm.

The width of each contact and the clearance between any two adjacentcontacts may be changed appropriately if needed or desired. For example,the width of each contact in the circumferential direction may beincreased or decreased by a unit of 1/10 mm (by several tenthsmillimeters) and the clearance between any two adjacent contacts in thecircumferential direction may be changed appropriately accordingly by aunit of 1/10 mm (by several tenths millimeters, for example, ±0.2 mm).

The contact LP3 is arranged at a position adjacent to the contact LP2.The contact LP5 is next to the contact LP6. The contact LP4 is arrangedbetween the contact LP3 and the contact LP5. The contact LP7 is arrangednext to the contact LP6. The contact LP8 is arranged next to the contactLP9.

Focusing on the contacts that supply voltage from the camera body 100 tothe interchangeable lens 200, the contacts are arranged as follows. Thetwelve contacts LP1 to LP12 are arranged in a circular arc in theholding unit 202. The contact LP12 is arranged at one end of thecircular arrangement and the contact LP1 is arranged at the other end ofthe circular arrangement. The contact LP11 is arranged next to thecontact LP12 and the contact LP2 is arranged next to the contact LP1.The contacts LP3 to LP6 are arranged next to the contact LP2 in the formof a circular arc. The contacts LP7 to LP10 are arranged next to thecontact LP11 in the form of a circular arc.

That is, among the contacts arranged in a circular arc the contacts LP1,LP11 that supply source voltage are arranged on both ends thereof. Thecontacts LP2 and LP11, which are ground terminals corresponding to thesource voltage, are arranged by one contact inner than the contacts LP1and LP12. The other communication system contacts LP3 to LP10 arearranged between the two contacts LP2, LP11, which are ground terminals.

The construction in which the contacts LP3 to LP10, which are contactsfor the communication system (communication system contacts), and thecontacts LP1 and LP12, which are power source system contacts thatsupply the power source voltage (the above-mentioned operation voltageand driving voltage) are intervened by the contacts LP2 and LP11 whichare ground terminals therefor, is adopted in order to minimizeinfluences that the power source system contacts (signal line) wouldgive on the communication system contacts (signal line).

The signal line (i.e., signal line that includes LP1 and LP12) thatsupplies source voltage yields a large change in voltage in response toa change in load in a supply destination to which the source voltage issupplied. The large change in voltage may give adverse influences on thecommunications signal line. According to the present embodiment, ameasure is taken to suppress the adverse influence as follows. That is,the contacts for ground terminals (ground contacts LP2 and LP11), whichare more stable with respect the change in voltage than the power sourcecontacts (LP1 and LP12), are arranged as intervening between thecommunication system contacts LP3 to LP10 and the power source contactsLP1, LP12.

The contacts LP3 to LP6 connected to the lens-side first communicationunit 217 and the contacts LP7 to LP10 connected to the lens-side secondcommunication unit 218 are arranged next to each other. On the contrary,the contacts LP3, LP4, and LP5 of the lens-side first communication unit217 and the contacts LP9, LP10 of the lens-side second communicationunit 218 are arranged such that the contacts belonging to onecommunication unit (217 or 218) are not arranged next to the contactsbelonging to different (the other) communication unit (218 or 217). Thatis, at positions near the contacts connected to the different (other)communication unit, the contacts LP6, LP7, and LP8 are arranged in lump.This is because the contacts LP6, LP7, and LP8 are designed to transmitsignals that do not synchronize with a clock signal (i.e., signals thatwill change to a relatively less extent as compared with the clocksignal or a signal synchronizing therewith, for example, signals whosestate change per unit time is on the order of 1 kilo Hertz (kHz) toseveral kilo Hertz (kHz)). Generally, the clock signal or signalsynchronizing therewith will change vigorously to such an extent thatchange per unit time is on the order of several mega Hertz (MHz) (forexample, in the case where the clock signal is at 8 MHz and data signalsynchronizing therewith is 4 MHz (though depending on the amount ofdata)), they tend to be a source of noises. Therefore, it is desirablethat such a terminal be arranged remote from the contacts connected tothe different (other) communication unit so that the influence oncommunication can be minimized. Accordingly, in the present embodiment,the following countermeasure is adopted. That is, the group of thecontacts that transmit signals that do not synchronize with the clocksignal (contacts LP6, LP7, LP8) are arranged so as to intervene betweenthe group of the contacts that transmit clock signal or signalssynchronizing therewith (contacts LP3, LP4, LP5) in the lens-side firstcommunication unit 217 and the group of the contacts that transmit theclock signal or signals synchronizing therewith in the lens-side secondcommunication unit 218 (contacts LP9, LP10).

The contacts LP7 to LP10 are arranged nearer the second power circuit121 with respect to the contacts LP3 to LP6 whereas the contacts LP3 toLP6 are arranged nearer the first power circuit 120 with respect to thecontacts LP7 to LP10. This is because the contacts LP7 to LP10 are lessinfluenced by noises. The second power circuit 121 supplies power to thelens driving unit 212. The power consumption by the lens driving unit212 changes considerably depending on whether or not the focusing lens210 b is driven. Therefore, the intensity of current that flows throughthe contact LP11 changes considerably, so that the influence on thecontact belonging to the adjacent communication system is greater thanthat given by the contact LP2. However, as described later,communication using the contacts LP7 to LP10 is of a shorter period thancommunication using the contacts LP3 to LP6 (that is, the period inwhich the communication is performed using the contacts LP7 to LP10 ison the order of 1/10 or less of the period of the communicationperformed using the contacts LP3 to LP6 and though described later, inthe present embodiment, the communication performed using the contactsLP7 to LP10 is at a period of 16 msec whereas the communicationperformed using t e contacts LP3 to LP6 is at a period of 1 msec). As aresult, even if the communication fails due to the influence of thecontact LP11, the communication can be performed again immediately. Inother words, the contacts LP7 to LP10 receive less influence by noisesthan the contacts LP3 to LP6 even when they are arranged next to thecontact LP11.

The contact LP10 is arranged next to the contact LP11. This is becausethe contact LP10 is more resistant to noises than the contact LP9. Asdescribed later, the clock signal is transmitted through the contact LP9and data signal that synchronize with the clock signal are transmittedthrough the contact LP10. The clock signal cannot be synchronized on thereceiving side when the leading edge or falling edge thereof becomesvague due to influences by noises. On the other hand, the data signal issampled with respect to signal level at the timing of leading edge orfalling edge of the clock signal. Therefore, it is only necessary thatthe signal level is clear at the above-mentioned timing, so that thedata signal has a higher resistance to noises than the clock signal.

The contacts BP1 to BP12 arranged in the holding unit 102 on the camerabody 100 side shown in FIG. 4B are the same as the above-mentionedcontacts LP1 to LP12 on the interchangeable lens 200 side. Accordingly,explanation thereof is omitted. As will be apparent from FIGS. 1, 4A and4B, the mount 101 on the camera body side is configured such that it canbe engaged with the mount 201 on the interchangeable lens side by firstfacing the both mounts 101 and 201 each other and then rotating one withrespect to the other. Therefore, the order in which the contacts BP1 toBP12 are arranged in the circumferential direction is in reverse to theorder in which the contacts LP1 to LP12 are arranged in thecircumferential direction as shown in FIGS. 4A and 4B. That is, in FIGS.4A and 4B, the contact LP1 is at the leftmost position and the contactLP12 is at the rightmost position whereas the contact BP1 is at therightmost position and the contact BP12 is at the leftmost position.

Explanation on Command Data

The lens-side control unit 203 controls the lens-side firstcommunication unit 217 to receive control data from the body-side firstcommunication unit 117 and transmit response data to the body-side firstcommunication unit 117 through the contacts LP3 to LP6, i.e., the signallines CLK, BDAT, LDAT, and RDY concurrently in a first predeterminedperiod (16 msec in the present embodiment). Hereafter, details of thecommunication performed between the lens-side first communication unit217 and the body-side first communication unit 117 is explained.

In the present embodiment, the communication performed between thelens-side control unit 203 and the lens-side first communication unit217 and the body-side control unit 103 and the body-side firstcommunication unit 117 is referred to as “command data communication”.

FIG. 5 presents a timing chart illustrating an example of command datacommunication. The body-side control unit 103 and the body-side firstcommunication unit 117 first check a signal level of the signal lineRDY. The signal level of the signal line RDY indicates whether or notthe communication of the lens-side first communication unit 217 ispossible. The lens-side control unit 203 and the lens-side firstcommunication unit 217 output a signal at a high (H) level through thecontact LP6 when communication is impossible. That is, the level of thesignal line is set to an H level. When the signal line RDY is at an Hlevel, the body-side control unit 203 and the body-side firstcommunication unit 117 will not start communication until the signalline RDY becomes at an L (low) level. During communication, thefollowing processes are not performed.

When the signal line RDY is at the L (low) level, the body-side controlunit 103 and the body-side first communication unit 117 output a clocksignal 401 through the contact BP3. That is, the body-side control unit103 and the body-side first communication unit 117 transmit the clocksignal 401 to the lens-side first communication unit 217 via the signalline CLK. The body-side control unit 103 and the body-side firstcommunication unit 117 outputs a body-side command packet signal 402,which is a front half of the control data through the contact BP4 insynchronization with the clock signal 401. That is, the body-sidecontrol unit 103 and the body-side first communication unit 117 transmitthe body-side command packet signal 402 to the lens-side firstcommunication unit 217 via the signal line BDAT.

When the clock signal 401 is output in the signal line CLK, thelens-side control unit 203 and the lens-side first communication unit217 output a lens-side command packet signal 403, which is a front halfof the response data, through the contact LP5 in synchronization withthe clock signal 401. That is, the lens-side control unit 203 and thelens-side first communication unit 217 transmit the lens-side commandpacket signal 403 to the body-side first communication unit 117 via thesignal line LDAT.

The lens-side control unit 203 and the lens-side first communicationunit 217 set the signal level of the signal line RDY to an H level inresponse to completion of transmission of the lens-side command packetsignal 403 (T2). The lens-side control unit 203 starts a first controlprocess 404 (which will be described later).

When the first control process 404 is completed, the lens-side controlunit 203 gives a notice of completion of the first control process 404to the lens-side first communication unit 217. In response to thisnotice, the lens-side first communication unit 217 outputs a signal atan L level through the contact LP6. That is, the lens-side firstcommunication unit 217 sets the signal level of the signal line RDY toan L level (T3). The body-side control unit 103 and the body-side firstcommunication unit 117 outputs a clock signal 405 through the contactBP3 in response to this change in the signal level. That is, thebody-side control unit 103 and the body-side first communication unit117 transmit the clock signal 405 to the lens-side first communicationunit 217 via the signal line CLK.

The body-side control unit 103 and the body-side first communicationunit 117 output, through the contact BP4, a body-side data packet signal406, which is a rear half of the control data, in synchronization withthe clock signal 405. That is, the body-side control unit 103 and thebody-side first communication unit 117 transmit a body-side data packetsignal 406 to the lens-side first communication unit 217 via the signalline BDAT.

When the clock signal 405 is output in the signal line CLK, thelens-side control unit 203 and the lens-side first communication unit217 output a lens-side data packet signal 407, which is a rear half ofthe response data, through the contact LP5 in synchronization with theclock signal 405. That is, the lens-side control unit 203 and thelens-side first communication unit 217 transmit the lens-side datapacket signal 407 to the body-side first communication unit 117 via thesignal line LDAT.

The lens-side control unit 203 and the lens-side first communicationunit 217 again sets the signal level of the signal line RDY to an Hlevel in response to completion of transmission of the lens-side datapacket signal 407 (T4). The lens-side control unit 203 starts a secondcontrol process 408 (which will be described later).

The first control process 404 and the second control process 408performed by the lens-side control unit 203 are described hereafter.

For example, a case where the received body-side command packet signal402 is to request specified data from the interchangeable lens isdescribed. The lens-side control unit 203 performs, as the first controlprocess 404, an analysis process for analyzing the content of thecommand packet signal 402 and a process for generating the requestedspecified data. Further, the lens-side control unit 203 performs, as thefirst control process 404, communication error check process in whichwhether an error has occurred in the communication of the command packetsignal 402 is easily checked by based on the number of bytes of data byusing check sum data contained in the command packet signal 402. Thesignal of the specified data generated by the first control process 404is output to the camera body as a lens-side data packet signal 407. Inthis case, a body-side data packet signal 406, which is output from thecamera body after the command packet signal 402 has been output, is adummy data signal (containing check sum data) which is meaningless tothe interchangeable lens. In this case, the lens-side control unit 203performs the above-mentioned communication error check process using thecheck sum data contained in the body-side data packet signal 406 as thesecond control process 408.

For example, a case where the received body-side command packet signal402 is, an instruction to drive a driven member in the lens isdescribed. For example, a case where the command packet signal 402 is aninstruction to drive the focus lens 210 b and the received body-sidedata packet signal 406 indicates an amount of drive of the focus lens210 b is described. The lens-side control unit 203 performs, as thefirst control process 404, an analysis process for analyzing the contentof the command packet signal 402 and generates a roger signal indicatingthat the content of the command packet signal 402 has been understood.Further, the lens-side control unit 203 performs, as the first controlprocess 404, the communication error check process as mentioned above byusing the check sum data contained in the command packet signal 402. Theroger signal generated in the first control process 404 is output to thecamera body as a lens-side data packet signal 407. The lens-side control203 performs, as the second control process 408, an analysis process foranalyzing the content of the body-side data packet signal 406 and thecommunication error check process as mentioned above by using the checksum data contained in the body-side data packet signal 406.

When the second control process 408 is completed, the lens-side controlunit 203 gives a notice of completion of the second control process 408to the lens-side first communication unit 217. After this, the lens-sidecontrol unit 203 controls the lens-side first communication unit 217 tooutput a signal at an L level through the contact LP6. That is, thesignal level of the signal line RDY is set to an L level (T5).

When the received body-side command packet signal 402 is an instructionto drive the lens-side driven member (for example, a focusing lens) asmentioned above, the lens-side control unit 203 controls the lens-sidefirst communication unit 217 to set the signal level of the signal lineRDY to an L level and controls the lens driving unit 212 to perform aprocess to drive the focus lens 210 b by the amount of drive instructed.

Each communication performed in a period from time T1 to time T5constitutes a command data communication at one time. As mentionedabove, in the command data communication at one time, one body-sidecommand packet signal 402 and one body side-data packet signal 406 aretransmitted by the body-side control unit 103 and the body-side datapacket signal 406, respectively. That is, although separatelytransmitted for the sake of convenience of processing, the two data,i.e., the body-side command packet signal 402 and the body-side datapacket signal 406 constitute a single piece of control data.

Similarly, in the command data communication at one time, one lens-sidecommand packet signal 403 and one lens-side data packet signal 407 aretransmitted by the lens-side control unit 203 and the lens-side firstcommunication unit 217, respectively. That is, the lens-side commandpacket signal 403 and the lens-side data packet signal 407 togetherconstitute one piece of response data.

As mentioned above, the lens-side control unit 203 and the lens-sidefirst communication unit 217 receive control data from the body-sidefirst communication unit 117 and transmit response data to the body-sidefirst communication unit 117 concurrently. The contacts LP6 and BP6 usedin the command data communication are contacts, through which otherasynchronous signals that are not synchronized with the clock signal(the signal level of the signal line RDY being H (High) level or L (low)level) are transmitted.

Explanation on Hot-line Transmission

The lens-side control unit 203 controls the lens-side secondcommunication unit 218 to transmit lens position data to the body-sidesecond communication unit 118 through the contacts LP7 to LP10, i.e.,via the signal lines HREQ, HANS, HCLK, and HDAT. Hereafter,communication performed between the lens-side second communication unit218 and the body-side second communication unit 118 is explained indetail.

In the present embodiment, the communication performed between thelens-side control unit 203 and the lens-side second communication unit218 and the body-side control unit 103 and the body-side secondcommunication unit 118 is referred to as “hot-line communication”.

FIG. 6 presents a timing chart illustrating an example of hot-linecommunication. The body-side control unit 103 according to the presentembodiment is configured such that hot-line communication is started forevery second predetermined period (for example, 1 msec in the presentembodiment). This period is shorter than the period in which the commanddata communication is performed. FIG. 6A presents a diagram illustratinga state in which hot-line communication is performed for everypredetermined period Tn. FIG. 6B illustrates a state in which a time Txrequired for one communication among repeatedly performed hot-linecommunications is shown in magnification. Hereafter, the procedure ofhot-line communication is explained with reference to the timing chartshown in FIG. 6B.

The body-side control unit 103 and the body-side second communicationunit 118 first output a signal at an L level through the contact BP7 atthe time of start of the hot-line communication (T6). That is, thesignal level of the signal line HREQ is set to an L level. The lens-sidesecond communication unit 218 gives a notice indicating that the signalis input to the contact LP7 to the lens-side control unit 203. Inresponse to this notice, the lens-side control unit 203 starts executionof a generation process 501 to generate lens position data. Thegeneration process 501 is a process in which the lens-side control unit203 controls a lens position detection unit 213 to detect the positionof the focus lens 210 b and generate lens position data that representsa result of the detection.

When the lens-side control unit 203 has completed execution of thegeneration process 501, the lens-side control unit 203 and the lens-sidesecond communication unit 218 output a signal at an L level through thecontact LP8 (T7). That is, the signal level of the signal line HANS isset to an L level. The body-side control unit 103 and the body-sidesecond communication unit 118 output a clock signal 502 through thecontact BP9 in response to the inputting of the signal in the contactBP8. That is, body-side control unit 103 and the body-side secondcommunication unit 118 transmit the clock signal to the lens-side secondcommunication unit 218 via the signal line HCLK.

The lens-side control unit 203 and the lens-side second communicationunit 218 output a lens position data signal 503 through the contact LP10in synchronization with the clock signal 502. That is, lens-side controlunit 203 and the lens-side second communication unit 218 transmit thelens position data signal 503 to the body-side second communication unit118 via the signal line HDAT.

When the transmission of the lens position data signal 503 is completed,the lens-side control unit 203 and the lens-side second communicationunit 218 output a signal at an H level through the contact LP8. That is,the signal level of the signal line HANS is set to an H level (T8). Thebody-side second communication unit 118 outputs a signal at an H levelthrough the contact LP7 in response to the inputting of the signal intothe contact BP8. That is, the signal level of the signal line HREQ isset to an H level (T9).

The communications performed during a period from time T6 to time T9constitute a hot-line communication at one time. As mentioned above, inthe hot-line communication at one time, only one lens position datasignal 503 is transmitted by the lens-side control unit 203 and thelens-side second communication unit 218. The contacts LP7, LP8, BP7, andBP8 that are used for the hot-line communication are other contactsthrough which asynchronous signals that are not synchronized with theclock signal are transmitted. That is, the contacts LP7 and BP7 arecontacts through which asynchronous signal (the signal level of thesignal line HREQ being H (High) level, or L (low) level) aretransmitted. The contacts LP8 and BP8 are contacts through whichasynchronous signal (the signal level of the signal line HANS being H(High) level, or L (low) level) are transmitted.

The command data communication and the hot-line communication can beperformed either simultaneously or partially concurrently. That is, oneof the lens-side first communication unit 217 and the lens-side secondcommunication unit 218 can perform communication with the camera body100 even when the other of them is performing communication with thecamera body 100.

With the camera system according to the first embodiment as describedabove, the following advantageous effects can be obtained.

(1) At the holding unit 202 on the lens mount 201, there are arranged ina circular arc the contact LP3 through which the clock signals 401, 405are transmitted from the camera body 100, the contact LP4 through whichthe body-side command packet signal 402 and the body-side data packetsignal 406 are transmitted in synchronization with the clock signals401, 405, the contact LP5 through which the lens-side command packetsignal 403 and the lens-side data packet signal 407 are transmitted tothe camera body 100 in synchronization with the clock signals 401, 405,and the contact LP6 through which asynchronous signals that are notsynchronized with the clock signals 401, 405 are transmitted to thecamera body 100. At the holding unit 202 on the lens mount 201, thereare arranged in the direction of an extension of a circular arc thecontact LP9 through which the clock signal 502 is transmitted from thecamera body 100, the contact LP10 through which the lens position datasignal 503 is transmitted to the camera body 100 in synchronization withthe clock signal 502, the contact LP7 through which an asynchronoussignal that is not synchronized with the clock signal 502 is transmittedfrom the camera body 100, and the contact LP8 through which anasynchronous signal that is not synchronized with the clock signal 502is transmitted to the camera body 100. The lens-side first communicationunit 217 receives control data from the camera body 100 and transmitsresponse data to the camera body 100 through the contacts LP3 to LP6concurrently. The lens-side second communication unit 218 transmits lensposition data to the camera body 100 through the contacts LP7 to LP10.One of the lens-side first communication unit 217 and the lens-sidesecond communication unit 218 can perform communication with the camerabody 100 even when the other of them performs communication with thecamera body 100. The contact LP6 is arranged at a position closer to thecontacts LP7 to LP 10 than to the contacts LP3 to LP5. The contacts LP7and LP8 are arranged at positions closer to the contacts LP3 to LP6 thanthe contacts LP9 and LP10 are. With this construction, influences of thecommunication by one of the two independent communication systems uponthe communication by the other can be minimized.

(2) At the holding unit 202 on the lens mount 201, there are arrangedthe contact LP12 through which the driving voltage of the lens driveunit 212 is supplied from the camera body 100, and the contact LP11which serves as a ground terminal corresponding to the drive voltage ina direction of extension in a circular arc. Here, the contacts LP7 toLP10 are arranged between the contacts LP3 to LP6 and the contacts LP10,LP11. The contact LP10 is arranged next to the contact LP11. With thisconstruction, influences of the signal line BAT via which drive voltageof the driving unit 212 on the signal line via which hot-linecommunication is performed can be minimized.

(3) At the holding unit 202 on the lens mount 201, there are arrangedthe contact LP1 through which operation voltages for command datacommunication and hot-line communication (i.e., operation voltages forthe lens-side first communication unit 217 and the lens-side secondcommunication unit 218) are supplied from the camera body 100 and thecontact LP2 that serves as a ground terminal corresponding to theoperation voltages in a direction of extension of in a circular arc.Here, a difference between an upper limit and a lower limit of currentthat flows through the contact LP11 is greater than a difference betweenan upper limit and a lower limit of current that flows through thecontact LP2. The contacts LP3 to LP6 are arranged between the contactsLP7 to LP10 and the contacts LP1, LP2. The contact LP2 is arranged at aposition closer to the contacts LP3 to LP6 than the contact LP1 is. Withthis construction, influences of the signal line V33 on the signal linefor command data communication can be minimized. Influences of a changein current that flows in the signal line PGND upon the signal line ofthe communication system can be minimized.

(4) The contact LP3 is arranged next to the contact LP2. The contact LP5is arranged next to the contact LP6. The contact LP4 is arranged betweenthe contacts LP3 and LP5. The contact LP7 is arranged next to thecontact LP6. The contact LP8 is arranged next to the contact LP9. As aresult, influences by noises that occur between the respective contactscan be minimized.

(5) At the holding unit 202 on the lens mount 201, there are arranged inthe form of a circular arc twelve contacts: the contact LP12 throughwhich drive voltage for operating the lens driving unit 212 is suppliedfrom the camera body 100; the contact LP11 which is a ground terminalcorresponding to the drive voltage; the contact LP3 through which theclock signals 401, 405 are transmitted from the camera body 100; thecontact LP4 through which the body-side command packet signal 402 andthe body-side data packet signal 406 are transmitted from the camerabody 100 in synchronization with the clock signals 401, 405; the contactLP5 through which the lens-side command packet signal 403 and thelens-side data packet signal 407 are transmitted to the camera body 100in synchronization with the clock signal 401, 405; the contact LP9through which the clock signal 502 is transmitted from the camera body100; the contact LP10 through which the lens position data signal 503 istransmitted to the camera body 100 in synchronization with the clocksignal 502; the contact LP6 through which an asynchronous signal that isnot synchronized with any of the clock signals 401, 405 and 502 istransmitted to the camera body 100; the contact LP7 through which anasynchronous signal that is not synchronized with any of the clocksignals 401, 405 and 502 is transmitted from the camera body 100; thecontact LP8 through which an asynchronous signal that is notsynchronized with any of the clock signals 401, 405 and 502 istransmitted to the camera body 100; the contact LP1 through whichoperation voltages for the lens-side first communication unit 217 andthe lens-side second communication unit 218 are supplied from the camerabody 100; and the contact LP2 which is a ground terminal correspondingto the operation voltages. Here, the contact LP12 is arranged on one endof the sequence of the twelve contacts and the contact LP1 is on theother end of that sequence. The contact LP11 is arranged next to thecontact LP12 and the contact LP2 is arranged next to the contact LP1.With this construction, influences on the communication system by noisesfrom outside can be suppressed.

(6) The contacts LP3, LP4, LP5, and LP6 are arranged next to the contactLP2 in the form of a circular arc. The contacts LP7, LP8, LP9, and LP10are arranged next to the contact LP11 in the form of a circular arc.With this construction, mutual influences between two independentcommunication lines can be minimized.

Modifications described below are within the scope of the presentinvention and one or more variations may be combined with theabove-mentioned embodiment(s).

Variation 1

In the above-mentioned embodiments, a plurality of contacts is arrangedin a single row along the edge of the mount as shown in FIGS. 4A and 4B.The plurality of contacts may be arranged in a single row in a formother than that shown in FIGS. 4A and 4B. For example, a plurality ofcontacts may be arranged in a straight line. The plurality of contactsmay be arranged at any desired positions of the lens mount 101, 201.FIGS. 4A and 4B show the arrangement of the plurality of contacts on thelower part of the respective lens mounts 101 and 201. However, they maybe arranged on the upper part of the lens mounts 101, 201 or on bothsides of the lens mounts 101, 201.

Variation 2

In the above-mentioned embodiment, the position data of the focus lens210 b has been explained to be transmitted from the interchangeable lens200 to the camera body 100 by hot-line communication. However, thesystem may be configured such that state information of a driven memberother than the focus lens can be transmitted by hot-line communication.For example, when the interchangeable lens 200 is provided with an imageblur correction lens, the position (X- and Y-position) of the image blurcorrection lens may be transmitted. Alternatively, the position ofdiaphragm in the interchangeable lens (information related to thediaphragm aperture size) may be transmitted. When the interchangeablelens is a zoom lens, information on focal length may be transmitted. Inthis case, the generation process 501 shown in FIG. 6B includes aprocess for the generation of data of the position of the image blurcorrection lens, a process for the generation of data of controlposition of the diaphragm that forms a diaphragm aperture (informationon position corresponding to aperture size), and a process for thegeneration of the data of the position of the zoom lens.

Variation 3

In the above-mentioned embodiment, the holding unit 102 (on the bodyside) and the holding unit 202 (on the interchangeable lens side) areeach formed as an integrated component (a single component). However,the holding units 102 and 202 may each be configured to include aplurality of holding unit components divided into several groups(corresponding to respective contacts) which can be combined to providean integrated holding unit.

Variation 4

In the above-mentioned embodiment, separate communication interfaces areprovided for two types of communications (i.e., hot-line communicationand command data communication). However, these interfaces may beintegrated into a single interface. That is, referring to theinterchangeable lens, the lens-side first communication unit 217 and thelens-side second communication unit 218 may be configured as oneintegrated unit. Similarly, referring to the camera body, the body-sidefirst communication unit 117 and the body-side second communication unit118 may be configured as one integrated unit. Further, a body-sidecontrol unit and a lens-side control unit each having the function ofsuch a communication interface may be used instead of the body-sidecontrol unit 103 and the lens-side control unit 203.

Variation 5

In the above-mentioned embodiment, the camera system including thecamera body 100 and the interchangeable lens 200 has been described.However, the present invention is not limited to camera systems. Theconstruction (the construction of the camera body) explained in theabove-mentioned embodiment may be applied to any electronic device thatincludes a mount to which the interchangeable lens 200 can be detachablyattached, is communicable with the interchangeable lens 200, and cansupply power to the interchangeable lens 200. An example of such anelectronic device is a projector. By configuring the projection lenscomponent of a projector as a projection lens that can be detachablyattached and interchangeable, a projector system similar to theabove-mentioned embodiment can be obtained.

Variation 6

In the above-mentioned embodiment, explanation has been made on theimage blur correction mechanism including an image blur correction lensthat can move so as to have a motion vector containing a component inthe direction perpendicular to the direction of optical axis of theimaging optical system 210 and can perform image blur correction bydriving the image blur correction lens. However, the image blurcorrection mechanism is not limited to the above-mentioned one but maybe one which performs image blur correction by rotating or swinging theimage blur correction optical system in the pitching direction and theyawing direction of the camera system.

According to the above embodiments, an influence of the communicationperformed by one of two independent communication systems on thecommunication performed by the other of the communication systems can beminimized.

The present invention is not limited to the above-mentioned embodimentand various forms may be conceived within the technical concept of thepresent invention so far as the features of the present invention arenot damaged. Such forms are also included within the scope of thepresent invention.

What is claimed is:
 1. A camera body to which an interchangeable lenscan be detachably attached, the camera body comprising: a first contactthat sends camera data to the interchangeable lens using a first clocksignal; a second contact that receives first lens data from theinterchangeable lens using the first clock signal; a third contact thatreceives second lens data different from the first lens data from theinterchangeable lens using a second clock signal different from thefirst clock signal; and a fourth contact that supplies to theinterchangeable lens an operation voltage that is different from a drivevoltage used for driving a lens, wherein the first and second contactsare arranged between the fourth contact and the third contact.
 2. Acamera body to which an interchangeable lens can be detachably attached,the camera body comprising: a first contact that sends camera data tothe interchangeable lens using a first clock signal; a second contactthat receives first lens data from the interchangeable lens using thefirst clock signal; a third contact that receives second lens datadifferent from the first lens data from the interchangeable lens using asecond clock signal different from the first clock signal; a fourthcontact that supplies to the interchangeable lens an operation voltagethat is different from a drive voltage used for driving a lens; and afifth contact that is a ground terminal for the operation voltage,wherein the fifth contact is arranged between the fourth contact and thefirst, second, and third contacts.
 3. A camera body to which aninterchangeable lens can be detachably attached, the camera bodycomprising: a first contact that sends camera data to theinterchangeable lens using a first clock signal; a second contact thatreceives first lens data from the interchangeable lens using the firstclock signal; a third contact that receives second lens data differentfrom the first lens data from the interchangeable lens using a secondclock signal different from the first clock signal; a fourth contactthat supplies to the interchangeable lens an operation voltage that isdifferent from a drive voltage used for driving a lens; and a fifthcontact that is a ground terminal for the operation voltage, wherein thefirst and second contacts are arranged closer to the fifth contact thanis the third contact, and the first and second contacts are arrangedcloser to the fifth contact than they are to the fourth contact.
 4. Thecamera body according to claim 1, further comprising: a sixth contactthat communicates the second clock signal, wherein the sixth contact isarranged at a position closer to the fourth contact than is the thirdcontact.
 5. The camera body according to claim 1, further comprising: aseventh contact that outputs the first clock signal to theinterchangeable lens, wherein the seventh contact is arranged at aposition closer to the fourth contact than is the second contact.
 6. Thecamera body according to claim 2, further comprising: a sixth contactthat communicates the second clock signal, wherein the sixth contact isarranged at a position closer to the fourth contact than is the thirdcontact.
 7. The camera body according to claim 2, further comprising: aseventh contact that outputs the first clock signal to theinterchangeable lens, wherein the seventh contact is arranged at aposition closer to the fourth contact than is the second contact.
 8. Thecamera body according to claim 3, further comprising: a sixth contactthat communicates the second clock signal, wherein the sixth contact isarranged at a position closer to the fourth contact than is the thirdcontact.
 9. The camera body according to claim 3, further comprising: aseventh contact that outputs the first clock signal to theinterchangeable lens, wherein the seventh contact is arranged at aposition closer to the fourth contact than is the second contact. 10.The camera body according to claim 1, further comprising: a fifthcontact that is a ground terminal for the operation voltage.
 11. Thecamera body according to claim 10, wherein the operation voltage is usedfor sending the first lens data and the second lens data to the camerabody.
 12. The camera body according to claim 2, wherein the operationvoltage is used for sending the first lens data and the second lens datato the camera body.
 13. The camera body according to claim 3, whereinthe operation voltage is used for sending the first lens data and thesecond lens data to the camera body.
 14. A device configured to bedetachably attached to a camera body, the device comprising: a firstcontact that receives camera data sent from the camera body using afirst clock signal; a second contact that sends first device data to thecamera body using the first clock signal; a third contact that sendssecond device data different from the first device data to the camerabody using a second clock signal different from the first clock signal;and a fourth contact that supplies, from the camera body, an operationvoltage to the device, the operation voltage being different from adrive voltage used for driving a lens, wherein the first and secondcontacts are arranged between the fourth contact and the third contact.15. A device configured to be detachably attached to a camera body, thedevice comprising: a first contact that receives camera data sent fromthe camera body using a first clock signal; a second contact that sendsfirst device data to the camera body using the first clock signal; athird contact that sends second device data different from the firstdevice data to the camera body using a second clock signal differentfrom the first clock signal; a fourth contact that supplies, from thecamera body, an operation voltage to the device, the operation voltagebeing different from a drive voltage used for driving a lens; and afifth contact that is a ground terminal for the operation voltage,wherein the fifth contact is arranged between the fourth contact and thefirst, second and third contacts.
 16. A device configured to bedetachably attached to a camera body, the device comprising: a firstcontact that receives camera data sent from the camera body using afirst clock signal; a second contact that sends first device data to thecamera body using the first clock signal; a third contact that sendssecond device data different from the first device data to the camerabody using a second clock signal different from the first clock signal;a fourth contact that supplies, from the camera body, an operationvoltage to the device, the operation voltage being different from adrive voltage used for driving a lens; and a fifth contact that is aground terminal for the operation voltage, wherein the first and secondcontacts are arranged closer to the fifth contact than is the thirdcontact, and the first and second contacts are arranged closer to thefifth contact than they are to the fourth contact.
 17. The deviceaccording to claim 14, further comprising: a sixth contact thatcommunicates the second clock signal, wherein the sixth contact isarranged at a position closer to the fourth contact than is the thirdcontact.
 18. The device according to claim 14, further comprising: aseventh contact to which the first clock signal output from the camerabody is configured to be input, wherein the seventh contact is arrangedat a position closer to the fourth contact than is the second contact.19. The device according to claim 15, further comprising: a sixthcontact that communicates the second clock signal, wherein the sixthcontact is arranged at a position closer to the fourth contact than isthe third contact.
 20. The device according to claim 15, furthercomprising: a seventh contact to which the first clock signal outputfrom the camera body is configured to be input, wherein the seventhcontact is arranged at a position closer to the fourth contact than isthe second contact.
 21. The device according to claim 16, furthercomprising: a sixth contact that communicates the second clock signal,wherein the sixth contact is arranged at a position closer to the fourthcontact than is the third contact.
 22. The device according to claim 16,further comprising: a seventh contact to which the first clock signaloutput from the camera body is configured to be input, wherein theseventh contact is arranged at a position closer to the fourth contactthan is the second contact.
 23. The device according to claim 14,further comprising: a fifth contact that is a ground terminal for theoperation voltage.
 24. The device according to claim 23, wherein theoperation voltage is used for sending the first device data and thesecond device data to the camera body.
 25. The device according to claim15, wherein the operation voltage is used for sending the first devicedata and the second device data to the camera body.
 26. The deviceaccording to claim 16, wherein the operation voltage is used for sendingthe first device data and the second device data to the camera body.